SINOKLE Heterogeneous Ozone Catalytic Oxidation: A New Approach to Landfill Leachate Treatment
1. Industry Dilemma and Technical Requirements in Leachate Treatment
Landfill leachate — the high-strength organic wastewater generated during the operation of landfills and incineration plants — is often called "the stubborn disease of wastewater". As waste generation keeps growing, leachate output in China has approached 80 million tonnes a year, and its composition has become ever more complex, containing more than 70 pollutants including aromatic hydrocarbons, halogenated compounds, heavy metals and various cancer promoters and co-carcinogens. Its key pollution indicators are extremely challenging: COD can reach tens of thousands of mg/L and ammonia nitrogen exceeds 1,000 mg/L, hundreds of times the levels in municipal sewage, posing a lethal threat to soil, groundwater and ecosystems.
Even more difficult, as landfills age, leachate biodegradability (BOD5/COD) plunges below 0.1 and refractory organics exceed 60%, so conventional processes generally hit a bottleneck. Membrane treatment (nanofiltration/reverse osmosis) gives stable effluent in the short term but suffers severe membrane fouling, high replacement costs and produces 15–30% hazardous concentrate that is hard to treat again; Fenton oxidation relies on large chemical doses, generates iron sludge hazardous waste that is difficult to dispose of, requires harsh conditions and its effluent easily regains colour; biological treatment (such as MBR) is limited by biodegradability, with effluent COD often above 1,000 mg/L and unable to meet discharge limits. Against this background, deep oxidation technologies combining efficient degradation, a low carbon footprint and stable operation have become the industry's breakthrough direction.
2. Core Principles and Advantages of SINOKLE Heterogeneous Ozone Catalytic Oxidation
To address these pain points, the heterogeneous ozone catalytic oxidation technology independently developed by SINOKLE overcomes the low efficiency and poor selectivity of conventional ozonation through the synergy of catalyst and ozone, achieving precise, deep mineralisation of refractory pollutants in leachate. Its core advantage lies in the heterogeneous catalyst: transition metal ions such as Cu, Fe and Mn are fixed onto a dedicated solid support by atomic deposition modification, forming a highly active, highly stable composite catalyst and avoiding the secondary pollution of metal-ion leaching and heavy sludge production typical of homogeneous catalysis.
During the reaction, SINOKLE's proprietary catalyst efficiently activates ozone to generate large amounts of ·OH radicals (redox potential as high as 2.8 V), giving non-selective oxidation of refractory organics and breaking complex pollutants down into harmless small molecules such as CO₂ and H₂O. At the same time, the catalyst's high specific surface area (over 250 m²/g) adsorbs pollutants and greatly raises the contact efficiency between ozone and pollutants, increasing the reaction rate 2–5 times over ozonation alone and shortening retention time to 5–15 minutes, only 1/8 to 1/4 of conventional oxidation.
3. Performance Comparison: Outperforming Conventional Processes Across the Board
SINOKLE heterogeneous ozone catalytic oxidation shows clear advantages in treatment efficiency, operating cost and environmental performance. The table below compares its key parameters with mainstream conventional processes:
Parameter | SINOKLE heterogeneous ozone catalytic oxidation | Conventional ozonation | Fenton oxidation | Membrane treatment |
COD removal | ≥85% (mature leachate) | 40%~60% | 60%~75% | ≥90% (but generates concentrate) |
Retention time | 5–15 min | 60–120 min | 30–60 min | 20–40 min |
Chemical consumption | Ozone only, no other chemicals | High ozone consumption | Very high Fe²⁺ salt and H₂O₂ consumption | Regular scale inhibitor and biocide dosing |
Secondary pollution | Zero hazardous waste, zero concentrate | No obvious secondary pollution, but low efficiency | Generates 10–15% hazardous iron sludge | Generates 15–30% hazardous concentrate |
Operating cost per tonne | CNY 30–50/t | CNY 60–80/t | CNY 50–70/t | CNY 100–150/t |
Service life | Catalyst service life ≥5 years | No catalyst; heavy equipment wear | No catalyst; severe equipment corrosion | Membrane element life 1–3 years |
Beyond these core advantages, the technology has three distinctive features: first, wide applicability, running stably across pH 3–11 without complex acid or alkali adjustment; second, intelligent O&M, with the whole train operating pressurised and enclosed and an AI monitoring system that adjusts ozone dosing in real time and cuts manual intervention by 70%; third, a compact footprint, since the skid-mounted integrated design occupies only one-third of the area of conventional processes and allows rapid installation and start-up.
4. Engineering Application Cases
To date, SINOKLE heterogeneous ozone catalytic oxidation has been running stably over long periods in leachate treatment projects at numerous landfills and incineration plants across China, with its performance proven in practice.
Case 1: leachate treatment at an ageing landfill in Hubei. Influent COD is 8,500–12,000 mg/L, ammonia nitrogen 1,200–1,500 mg/L and biodegradability only 0.08. With SINOKLE heterogeneous ozone catalytic oxidation as the tertiary unit, effluent COD falls steadily below 100 mg/L, ammonia nitrogen removal reaches 98% and colour is ≤30 (colourless and odourless), with every indicator better than the Class I limits of the Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889-2008). Operating cost is only CNY 42/t, 58% lower than the previous membrane process, and the burden of hazardous concentrate disposal is eliminated entirely.
Case 2: leachate treatment at a waste incineration plant in Guangdong. The leachate contains high concentrations of refractory organics and heavy metals, and effluent COD after a conventional Fenton + MBR process still exceeded 500 mg/L. After introducing SINOKLE heterogeneous ozone catalytic oxidation, final effluent COD is steadily below 80 mg/L, suspended solids removal is ≥99% and heavy metals meet limits; the system ran 18 months without failure, catalyst activity remained stable and no secondary pollution was produced.
With environmental regulations tightening and "zero-waste city" programmes accelerating, SINOKLE heterogeneous ozone catalytic oxidation — with its core strengths of full-quantity treatment, zero hazardous waste discharge and low operating cost — offers an efficient, practical solution for leachate treatment. Compared with conventional processes it not only raises efficiency substantially but avoids secondary pollution at the source, delivering both environmental and economic benefits.
Looking ahead, SINOKLE will continue to deepen its work in advanced oxidation, refining catalyst performance and process integration so that the technology can be applied in more challenging industrial wastewater scenarios, protecting clear water and blue skies through innovation and supporting high-quality ecological development.
